Herb-drug interactions: review and assessment of report reliability

Br J Clin Pharmacol. 2001 Nov;52(5):587-95. doi: 10.1046/j.0306-5251.2001.01469.x.


Aims: The aim of this systematic review was to assess the published clinical evidence on interactions between herbal and conventional drugs.

Methods: Four electronic databases were searched for case reports, case series or clinical trials of such interactions. The data were extracted and validated using a scoring system for interaction probability.

Results: One hundred and eight cases of suspected interactions were found. 68.5% were classified as 'unable to be evaluated', 13% as 'well-documented' and 18.5% as 'possible' interactions. Warfarin was the most common drug (18 cases) and St John's wort the most common herb (54 cases) involved.

Conclusion: Herb-drug interactions undoubtedly do occur and may put individuals at risk. However our present knowledge is incomplete and more research is urgently needed.

Publication types

  • Case Reports
  • Review
  • Systematic Review

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Cycadopsida*
  • Databases as Topic
  • Drug Interactions*
  • Female
  • Herb-Drug Interactions
  • Humans
  • Magnoliopsida*
  • Male
  • Middle Aged
  • Phytotherapy* / adverse effects